Process of manufacturing and laying bituminous sheet-pavements and materials therefor.



' cmrronp nrciinnnsoiw, or NEW YORK, N. Y., .assienon 'ro THE BARBERASPHALT PAVING comrnny, or PHILADELPHIA, PENNSYLVANIA, A conroaa'rioiuor WEST raocnss or MANUFACTURING A II e BITUMINQUS- SEEETJ'AVEMENTS AMATERIALS 'IHEREFOBI.

1,090,792. No Drawing.

Specification of Iietters Iatent.

Pat nted lkflla W.

Application filed January 12, 1,810. Serial No. 587,641.

7 To all whom it may concern:

I 'Be it known that I, CLIFFORD RICHARD:

. son, of New York, in the county of New York and State of New York,have invented certain new and useful Improvements in the Process ofManufacturing and Laying .Bituminous Sheet-Pavements and Materials gateis combined with the bituminous eementing material, the rock oraggregate and the cement are mixed in proper proportions, each in aheated condition, and are placed, spread and compacted while still hot;or the bituminous cementing material is a plied to cold stone oraggregate immediate y on the spot where the work is being constructed orafter it has been constructed, and either before orafter it has beenputinto the surface. The former method requires immediate use of the hotcoated stone or aggregate before it has cooled, since on cooling itbecomes agglomerated into a mass which cannot be separated and properlymanipulated or spread if the original cementing material is ofsufficient density or consistency to have a satisfactorycementingacapacity.

y myv invention, while coating hot or warm stone with hot bituminouscementing material, I avoid the necessity of laying such material beforeit has cooled by producing it in a form in which each of-the coatedparticles can be readily separated, manipulated, spread and compacted toform a roadway surface, thus enabling the stone or mineral aggregate tobe coated with a bituminous cementing material of sufliciently hardconsistency at the quarry, crusher, or at a plant suitable for itspreparation, and enabling it afterward to be transported for anydistance and held for any length of time before its use without adhesionwhich will prevent its manipulation.

In the practice of my rocess I take stone of a character suitable or theconstruction of a bituminous macadam pavement or a combination ofmineral matter of different sizes as an aggregate for this purpose.stone or mineral aggregate is. heated and The mixed with a suitablequantity of a bituminous cementing medium, also liquefied by heat, themixture being effected mechanically or by hand or by any suitableniachinery. Instead of transporting this mixture and laying it while itstill retains its heat, suddenly chill and wet the hot mixture, eitherby a spray of cold water thrown upon it, or by dropping the entiremixture into a tank of cold water, The result of this sudden chillapplied by water at this step of the process, is that the stone ormineral aggregate and the bituminous ce-' ment are converted into a massin which the particles do not adhere to one another to such a degree asto prevent the mixture, even after storage if desired, from beingtransported, spread, manipulated and com pacted. The sudden chilling bywater is essential to the success of the process. The high specific heatof water not only-effects the chilling much more rapidly than can beaccomplished by other means, as for example by the use of cold air, butthe presence of water on the surface of the cooled asphalt greatlydecreases its adhesiveness, so that there is little or no adhesionbetween the separately cooled and wet lumps, and in this condition thewhole mass soon cools down to a temperature at which compaction is onlypossible under the pressure of a road roller.

If a mixture of hot stone or a mineral aggregate and hot bituminouscement, such as I have described were held for any lengthof time andallowed to cool in the air, without being chilled suddenly with water,it

would form a solid adhesive conglomerate mass, which would be incapableof being subsequently properly spread, laid and compacted as a pavementor road surface, but according to my method, the mass consisting .ofstone or aggregate and bituminous ce-w ment in proper proportions, isseparable as distinguished from conglomerate and its parts do not soadhere together as to prevent the mass from being properly spread,rolled and compacted to form a pavement or the surface of a highway.

In practice. the cold material is trans ported to the placewhere it isto be laid, where 'it is readily broken up or crumbled by rakes ortamping irons. It is thereupon ice by tamping and rolling, which processof compaction continues when the road is thrown open to rolling traflic.7

Having thus described my invention, I claim:

The process of manufacturing and laying a bituminous paving material,which consists in heating a stone or mineral aggregate and a bituminouscementing material, combining the two While hot, suddenly chilling andWetting the Anixture by application of cold water, and thereafterwithout reheating spreading and compacting the mixture to form apavement.

In testimony whereof, I have hereunto signed my name at New York citythis tenth day of January 1910.

CLIFFORD RICHARDSON.

VVitnessesz.

GEORGE WIRTH,

NORMAN SWEET.

